I bought the Givi 780FZ rear luggage rack for my 2010 M696. It mounts to the 4 bolts under the passenger area of the rear seat. Anyone ever remove those bolts? I can't get any one of them to budge without stripping out the 5mm allen head. I even have an impact driver punch (the kind you hit with a hammer and it forces down and turns at the same time) and that won't even break them loose. I can't heat the bolt because the rear bracket under the bolt is painted. Any ideas besides drilling them out? I'm guessing they are either locktighted in or the steel bolt corroded some to the aluminum (or magnesium) frame they are screwed into.